$500 for most 3D packages is just a start. Add on a zero and your into the realm of most of the professional packages.

Also make sure your computer is up to 3D. It takes some horsepower.

The latest issue of Cadalyst has a review of several "low cost" cad packages 3D and 2D.

Take a look at Alibre Design. They have a free 3D package that is quite good. That being said, the package is limited to the number of components you can put together in an assembly.

For most home remodeling stuff my opinion is to work with 2d for layout, floorplans, etc. If you want to really get a visualization of how something will look you can try tackling 3D. Basic geometric shapes will give you a good feel for the space if your trying to work out cabinet positioning or furnature layout. It is tempting to go overboard on details sometimes.

I found myself in the same situation. I'm hesitant to shell out the money most of those folks are asking so I've been playing around with "google sketch up". It's a real bare bones 3D modeling program, but it does fulfill most of my needs and it's free.

I use a pretty ancient thing from Brodurbund called 3D Home Architect 4.0. It has the 3d, draws walls, will even give a framing point of view, though I would hesitate to frame floors that way. Works nice.